This relates generally to integrated circuits, and more particularly, to integrated circuits with wireless communications circuitry.
Integrated circuits with wireless communications capabilities typically include amplifying circuits that are used to amplify the power of radio-frequency signals prior to wireless transmission. For example, a radio-frequency power amplifier may receive input signals having an input power level and generate corresponding output signals having an output power level, where the output power level of the output signal is generally greater than the input power level of the input signal. Ideally, the power amplifier exhibits a perfectly linear input-output power transfer characteristic (i.e., an increase in the input power by a certain amount should result in a corresponding predetermined amount of increase in the output power). In practice, however, power amplifiers often exhibit non-linear behavior. When a power amplifier is non-linear, an increase in the input power may result in a corresponding increase in the output power that is less than the predetermined amount. Amplifier non-linearity issues can degrade signal integrity and adversely impact wireless performance.
Wireless integrated circuits such as transceiver circuits are sometimes configured to support complex, non-constant envelope modulation schemes such as the Wideband Code Division Multiple Access (W-CDMA) modulation scheme and the Orthogonal Frequency-Division Multiplexing (OFDM) modulation scheme. High frequency signals generated using such types of radio access technologies can exhibit high peak-to-average ratios (PARs), which can adversely impact the efficiency of radio-frequency power amplifiers used in wireless base transceiver stations (as an example).
It would therefore be desirable to provide improved wireless communications circuitry that can mitigate amplifier non-linearity while limiting peak-to-average ratios of transmitted signals.